Underreamer.



w. L, DUNN.

UNDERHEIMER.` APPLICATION FILED IAN- 23,71911.

Patented Feb. 20, 1917' 3 SHEETSwSMEET 3.

f A. www

liar-DUNN, O'F -PAIRUQ CALIFORNIA, ASSIGNOR T0 UNN MANUFAGTURING c.; QOMBANY, lF OXNARD/CALIFORNIA, A CORPORATION 0F CALIFORNIA. y y

citivlen' "of the United States, residing at V.Pira-,filitlie'countyof Ventura and State of ffali-forrlia, vhave inventeda neT anduseful Underreamerfof which the following is a specification y,

This "invention relates to the class of well'- drillihg tools of'tlie'socalled churn drilling typein which the tool is reciprocated vertically'inthe'hole.

In theJ drilling ot' wells for oil and Water, etc.,` it is often necessary to put in long 'strings 'of' pipe, sometimes Vas `much as lfour' thousand feet of. one size -of pipe in one string in order lto complete a well'g'and it is desirable'to put in'as lunch pipe ofone Ysize as possible'beforereducing the size of the hole-by putting in" asmaller diameter of, ipige` y o` dojthfis' itis necessary to have an under- `reani'er;toolthat will 'passdown throughthe pip'eindfekpand underneath the pipe .to a. `diarneter largeenough to inake the holle un /dernjeaitlilthe' pip'e of'sulici'ent diameter to alloiifthe pipetoldescend. This becomes necessary in cases where one part of the formationis soft and liable to cave in and run into the hole and when another part thereunder i`sconiparatively hard or is very hard so asto forni a support for thepipe; which support lnust hereanied out before the pipe Will 'go d6\vn.

Underreainers of the Vreciprocating `type havejllere'toyfore been constructed for this purp'se bl'ltintheir use fit, is often found that ther liability'ofrealning.what is latmliole, that is to say, a hole that g in cross section; and w 'ere such 40`flat'frearning occurs the pipe will not go dorrfnl 'andlivl .heroine wedged inthe hole, thusfcafusing unich trouble and expense becausewtlie :pipe becomes squeezed fiat, the heavy :steel shoe solnetnnessphts and conies4 loose` .from the pipe thus requiring, to be drilled 1out orV causing the loss of the hole.

' The :formation of Hat Aholes |has been avoided in `working `with the realners hereto.- tore", knowirf hy. providing another tool knoiyngas af ratchet o'r sn-'irel Vsocket which i forces the lulderreainer.to rotate in thehole to someextent dining the reciprocating action. Such sockets 'are very expensiveandI theywear ontand get out of repairyery eas- UN DEBREAM'ER.

Specification of Letters Patent. Patnted Feb. 20, 1917'. 'i Application ined January 23;'1911. serial No. 604,261.

ily; this being caused by sand getting into the ball bearing parts and the ratchet parts ot' the swivel socket and grinding them away. l

Anv objectof this invention is to provide an underrea-xner of the reciprocating type to be used in churn drilling, which will not under any circumstances drill a. flat hole; thus 'doing away with the necessity. of the ratchet or swivel socket for turning the tool. It also often occurs with underreamers heretofore known, that as the underrearner proceeds through a practically solid but comparatively soft formation the roamed hole will be'rifled; that is to say, two oppositely disposed ridges will be left between the spiral grooves which arecut bythe two cutters of the underrealner and these ridges' are so solid and strong as toprev'ent-the tool from turning inthe hole. But the driller is una bvle to determine-'whether or no thehole has been igi'fied. It the hole 'has been riiied, such rifles will prevent the underrealner from turning when solid formation is again encountered and a flat hole through the solid formation would result.

In orderl to overcome this difficulty with former reciprocating underreainers it is necessary for the driller to pull back 4and reunderreain through the soft formation so as 'to insure that the underreamer will rotate during `the operation 'of underreaming through thehard formation below. A y An object of thisv invention isto do ,away

with the liability of any diiiicultythus arising.

Other objects`- of the invention are: strength; cheapness; simplicityease of operation; ease of inserting into and With- 4drawing from the hole; and durability.

Heretofore the standard reciprocating well-toolsknown as underreamers and'oper.- atable for realning out the hole beneath a well-casing have invariably terminated in xcutters the cutting edges'of which are relatively movable only in ahned paths; there being only tufo of such cutters to each tool and the edges of suoli tools being movable rela-tively only directly toward and from each other.

Such constructlon of the tool I1s the cause Aof rezligtningl flat and ritled holes for theres.`

son t At with a'tool so constructed, the. directing yforces that resultv from the contact of the cutting edges with the wall of the hole on two faces diametrically opposite eachother, tend, to `-prevent the tool from turning' responsive to the twist of the cable from which the tool is suspended, and the extent to which the tool will rotate at each -reciproeation will not lie sufficient to cause the cutters to cut out all material 'between verticalsdrawn from the ends of the cutand 1while expanding or' contracting said` ting edges. when the tool 4is at rest, and con -v seqiurntly the hole. is underreamed only on two oppositely disposed sides. andbetween .suchsides there are left two vridges,4 so that the hole thusworked onwill he only partly under'i'eained and will lie what is termed a fiat and rifled hole. B v providinga, recil'irocating uiide'rreainingv tool with three or more cutters. the directing forces will not-lie such as to prevent the twist of the cable fi'oiii turningr the tool sufficiently as it is reciprocated. so that it will cut'away material entirely around the hole and by arranging the cutter so that as the tool ex- 'pands and contracts the cutting edges move in relatively angular paths and-hy sup yplyingf as many cutters as can be accoinmo'- dated under" this arrangement in the lower end of the tool .body the interspaces hetilveen 'the' cutter edges are minimized.and by providing more than two cutters each having.

a. cutting edge the radius of which equalsthc radius of the underreainedhole, and the ends of which edges practically contact wlth'each` otherwhen the toolis collapsed to the 'damf eter of the easing under which the hole' is to he vreaiiied. the eut effected by the recipro-v .cating tool in operation will invariably-he truly cylindrical because the contactof the' tool at three or more symmetricallydisposed lines around the axis ofthe tool center the tool and. tlifL drilling of a so called Hat'hole will lie avoided. By this means Itlispense with vthe expensive ratchet socket.

In order to provide an underrea'mer which will invariably reain a round hole that will allow free descent of the pipe. I provide an Y iinderreainer having more than two cutters;

cutters niove relatively in paths that are in angular relation to each other and that are radial rela't'ivegto the axis of the under-- reamer.

.ln carrying out this inventionthrec or more cutters must he employed and they are constructed and arrangedto practically nest together when they are retracted for the purpose of'passing through the pipe 'below which the reain'ing -is to'he effected.' andto'` practically 'cover the entire circumference of a4 circle equal in diameter" to the extreme4 spread of the cutters. when ,the tool is Iin operation. I

lii the preferable form of my invention, I

provide a reamer with four knives or 'cutters which very readily pass down-through the pipe and when expanded underneath the y pipe almost fill the entire diameter of the hole. l

Another difficulty to be guarded against is `tlie liability of the tempered steel cutters to become detached from the body of the. underreamer and lostin the hole. When thus lost in the hole it is a very serious matter, as the cutters are very difficult to fish ont and almost jinvariabl-yf must vbe ivorn 7'5' |out bit hy bit, which is a very expensive that are only provided with two cutters 9o4 as they are now made and used. is that when they wear a little out of gage and get some wornsurfaceon the edge of the cutters 'theywill ofte'nbind and stick in the hole.

Thisnecessitates `running the machinery at acceleratedaspeed iin order to whipor jerk the reamer loose and it sometimes occurs thatfafter the reamer has thus been jerked loose it` is impossible to stop or slow down the speed of the engine quickly enough 16T 1 to hold the A\tools out o'f\tlie way and from plungiiigbackjwpith great force. and such plunging force'is often suflicient to break the-cutters in they well.

Practicalwell drillers haiie'come torecog- 10i.

nize this as one of the greatest dangers of attempting-'to use underreaniers. i

l `An object `ofthis invention is'to -fio-"conf vstruct the reamer as to avoid this trouble and danger; and-in order to accomplish. this thegbearings of t cptters varestepped and tap'ere dilitt o' a stepped andlta'pered boiz bod vof the reamer and are held.

in -the `box by the spring operated mandrel and ifthecutters should have a tendency to 115 bin'dor Astick,``the body of the reamer will on vthe upstroke, lift up oilofthe "tapered parts or' bearings of the cutters, thus immediately releasing the cutters and allowing them to contractv and thus become loose from' v1.20

the walls ofthe hole. l

lAnother-'great advantage to be attained bymy newlyinventerlreamer having morethan two cutters,is that ifthe reamer has passed down the holev .tor any dstancehelow'the 12.5' 'l pipe. it is certain that the pipe will also.` ass down the same distance without any;li al ility o flattenirigfthje pipe. This feature'of improved operation is one not heretofore attained by axiy'under-reamer and results in a 13:

i as to uiiniiiiiac the wear between the body of i .1,217,0se I provide an underfreanier. the body of which will have a longer life than `the bodies of underreaiucis vlicictotore known, 'and `which can be fitted with stock cutters, of u'niforin sli:ipe`,`iini(l.e from a teniplehsoas to avoid 'the present necessity of taking the body of the reaiiier to the shop'to fit itiiith cutters. l \iiothcr object is to so construct the tool thel tool and the shanks ofthe cutters.

.'lhe body ,of this ui'ider-.reainer diers from i'uideni'eainer bodies 'heretofore known iii that it terminates at its lower elitl in an uninterrupted circular 'edge or-rini inside of` which is provided-a stepped bowl-like cavity tapering from various angles from mouth to tip in which the cutters having shoulders pract".ally fitting the inside of the casing under which the reaining is to take place are seated and the ,cutters nest with and mutually support each otherv against inward thrust dining operation; and the cavity is of such forni that the vdownward thrust on thc cutters is made by the 'solid poi-tion of the body and does not jam or wear theedge ofthe body andtlie body is subject to but little wear where it contacts with the cutters.

A A' further object ofthe invention is to so construct the cutters and the body." which carries the saine,` that the cutters will act smoothly .and respond readily to the adjustv ing pressures for niovingthe cutters in to and outy of their seat in the body andto provide orielatively great radialiiioi-'einent of the cutters.

AThe accompanying drawings illustrate the i invention.

Fi gare l is a view of' the underreamer asit 'appears descending through a well casingv below whiclrtlie 'i'eaming is to be effected. Fig. 2 is a tiaginental detail showing the lower end. of the underreaniei' 1n operation below the casing sliowniii Figl 1.

VF is a view partly iii vertical midsection of: a fourcutter underieanier as nor iiially collapsed in a casing which is of reduced diameter just below to indicate the capabilityof the tog-.3l to further collapse. The mandrel and tlininandrel.spring areintact and -two of thecutters arefsectioned in the axiahplaiic of .the unilcrreanier.

Fig. fl is a vew looking up at-the bottom of the toohwheii collapsed in the-casing, as

shown in Figs. l and-3.

Fig. 5 'is aplaii section on 'line m5, F ig. 3. Fw. (i is a plansection on line m Fig. 3.

t 7 Fig. i is'a plan section .online m7, Fig. 3. Fig. 8 isa fragmentary sectional'view 'showingthe underreamer expanded and in 'practical use.

the mandrel.

Fig. 9 is a' view looking tomof Fig. 8.

up from the bot- Fig. 9*1L isa view off the bottoni of the body.

i Fig. 10 is a view of the mandrel and two oftlie cutters detached. The eye bolt for -pullng the mandrel downl to collapse the.`

Fig. Vis an elevation of the mandrel of l Fig. 12 detached.

Fig. 16 is a view of the bottom of the' body The under-remuer illustrated by Figs. 1 to.4 y

9, inclusive,l com rises a body 1 having a loii gitudinal bore oiniing the mandrel way 2' and provided at its lower end with a box having a downwardly flaring or upwardly reduced or 'tapered stepped seat 3 to receive the upwardly reduced or tapered upper ends or Shanks 0 of the assembled cutters 4.. Said,

cutters are vnested in the seat 3 and are held,

therein by a mandrel 5 which works in the mandrel way :and pivotally enga-ges the cutters'to. hold their Shanks' seated in the box. Said cut-ters project below saidbody and form the lower end of the tool.

The seat 3 and the Shanks of said cutters are correspondingly7 reduced in diameter,I

and the iniierinostfacesV of the cutters are sobentand thecutters are so pivoted on the mandrel that whenj the cutters are held up' in the seat, their Shanks are held compactly together and the blades or loweriends of the cutters are spreadjapa-rt; and when theautters are lowered in the seat, their blades may beoolla-psed or nested together to such extent as to allow the cutters to pass through a cas-` ing of.- any diameter-'that thebody` 1 will pass through.

.Themandiel 5 is yielding'ly upheld bythe mandrel spring 6 mounted in the .enlarged spring 4.chamber 7 of the mandrel way, and' is secured .by nuts 8, 9, on the upper end of The mandrel preferably formed with/a` Ic 7lindrical Ystem 10 at the upper part and said stem Works through the spring. The 4stein is angular `in cross section at the lower portion 11 which `work-sin the. lower part of the mandrel way 2 that practically corresponds in cross section' to the lower portion of the mandrel; thus to hold .the mandrel from turningin the bodys The mandrel 'is' izo preferably a-steel forging provided at its lower endswith four pivots 12 to engage in seatsl in lthe/inner sides of the cutters 4,

-and is made of a single piece with such pivots.. l

The inner side of each cutter is constructed in two plane faces 14. 15, angularly arranged relativel to each other so that the cutters will swing on the pivots 12; there being a fulcrum edge a between said faces at the top margin o the seat 13 between the shank and blade of each cutter.

The angle between the inner faces 1l and of the shank and blade is such that in the upright tool, the inner face 14: of the shank is vertical when the reainer is expandeddind the inner face 15 of the blade is practically vertical when the reamer is collapsed.

The cutters are interchangeable, all l)eing iliade alike and are appropriately dressed at the lower end soas to fornithe bottom tace 16 and the outer face 17 at such an angle with eachother as to produce the cutting edge lgwhich comes into play7 when the tool is expanded.. f

The outer'faces 17 of the cutter blades are practically cylinder segments having about the saine radius as the whole to be undei'- reamed and each segmental outer face extends upward from the cutting edge 18 for a distance that may be about one-half of the whole length of the cutter from cutting edge to tip of thev shank.

At the upper ends of tlie cutter blades and about midway between the ends of the cutV ter the outer face' of the cutter is provided nular sloping shoulder 21 against whici the rounded tip 22 of4 the cutter shank may impinge under'the impulse of the mandrel. Ispring after the mandrel. has been drawn -down through the'bodyso as to allow the base of the'rider Q0 to contact witlithe inside ofthe casing.

The sloping shoulder '21 is of greater width than the rounded tip 2:2 of the cutterffThe mandrelgfthebody; the sloping' shoulder -21 of the seat: and the tips 22, lower inner faces 15 Aand riders 20 'of the cutters, are relatively so arranged that while the tips are 4in contact with the shoulder the riders may he moved )utward to contact withthe inner wall o f a well casing of con siderably vgreater diameter than the body;

Vsaid tips being, ,iable' up and down on said shoulder. so that said ridersinay move'in and out to follow the irregularities of the casing in which the'body1 is being lowered or `the tool therein.

raised while said cutters are vheld ,in col lapsed position onthe mandrel by contact of the tips with the shoulder and of the riders with the casing down or .up which the body may move.

The body 1 is of a diameter somewhat smaller than the casing 19 for'which the I under-reamer-is designed, so as to afford the usual clearance required `to allowA free vertical movement of the body in theV casing; and the bases'of the riders are between the cutting edges andthe pivotal points' and edges of the cutters.

Bv reason ofthe stepped forin of the seat 3 Aand the reduced forms of the upper ends of the cutters, considerable play is provided .pinge upon the contracted portion; then,

upon descent of thetool in the casing. the

cutters would thereby be squeezed toward each other at their lower ends, thus bri-iiging the reduced upper ends of the cutters downward and outward into the -tlaringi mouth .of the seat 3, thereby allowing the tool to abnormally collapse to the dotted position in Fig. 3; the bases of. the riders being thus retracted,` toward the mandrel,

the cutters may pass through any space through which the bdy- 14 may pass al though normally.l the riders slide on the inner wall of the casing and tend to center spring G 'allows the cutters to iove down ward relative torthe body so that the abnormal collapsing may occur, and return the cutters to the normal collapsed position shown in solid lines vin Fig. '3, as Soon as the restricted bore or indentation d Vof the casing is passed. v. The box of the' sub :23 in tlieforms shown in Figs. 1. audit. is' recessed to accommodate the mandrel when the cutters are ex'- pa'nded as shown in Fig.` 8.

Thev spring` will normally 'be of such length that wh-e'nithe body, cutters and inandrel are assembled as shown in Fig. 8. and before the body is screwed into the sub, the nut S'may be started onto the `mandrel and may then be screwed down suiciently to In this operation the f give thev tension require-dto hold the cutters in their seatswhen thel tool issuspended. home and suicient play is left'between the 8 and the pinl e.V of'the'body `to allow e mandrel to be drawn down far enough to'fully collapse the tool in Vthe position indicated by dotted lines in Eig. 3. When the Then the 'jam' nut'9 may be screwed lnut 8V stopped by the end of the pin ye pivots andthe seat. i.

l't `is therefore necessary 1n the forms shown inFigs. l, 3 and 8, that the body shall be unscrewed from the sub 23 whenever it is necessary to remove the cutters" for sharpening.'

In some 1nstances,`as i-n they case of Vvery large andl heayyreamers, 4it isdesirable to `take out the cutters to resharpen them without `having to take the body of the underrealner from the string of tools and it is also dsirable that the pin of the underreamer body shall not be bored, thus to allow the use ofthe standard size tool pin'A 25 on the body. v

Figs.` 12, 13, 14 and 15 show the form of construction designed to allow the cutters to beremoved and replaced -whilethe body is carried by the string of tools.

" Iii-this form the mandrel bore 24 is cylindrical and of one diameter fromend to end and terminates short .of the pin25; and the body 2 6 is provided with counter-sunk trans verse bores ZTI-eady to receive set screws 28 .andy between saidtransverse bores and the seat 3 a transverse keyway 2'9 is provided to receive akey 30; andthe body 26 is cut away at both si'des of the key-way.

and on both sides of the body to `ormrecasses 31 to accommodate pins 32 that hold the key in place. The mandrel 33 is pro vided'at its lower end with the pivots 12 the same as in the other forms and above said pivots is provided with a ilat faced shank' to fit between the cutterst that correspond to the cutters shown in the'other views. AboveV theflat-'faced shank 34 the mandrel is providedvl with a cylindrical `en-v largement having a longitudinal slot 36 the length of which is greater than the width of the key 30 so that when the mandrel is in the bore and the key 30 is in place in' the body and extending 4through the mandrel, the mandrel can be drawn down only far enough to allow the cutters to fully colla ase. l lIn order to allow 'the' Shanks of the cutters to beremoved from the seat 3, the:key must be removed. 1 l l A spring seat 37 in the mandrel fits the bore 24 and' is'provided with two recesses B8 into which the ends'of the set-screws 28 may be screwed to hold the spring seat from moving along the bore. 3 The spring Gis secured on the mandrel by .the nut.l 8: and

in Figs. 3 and 8r- .The usual open ring 39 is provided to hold tla. cutters 'in the nested position shown in Figs. 1 and 3 until rml into the casing..A

'in their nested `below` the bottom of the casing, they ymove Aradially relative to the axis yot theI 'Figs 12Hand 8, where'theycoi r done away with.

9 as in the form shown theyv have been in? Themandrel is'provided 5'5,

socket 40-for the eye bolt filby which ythe i -mandreL can be drawn down ,toallowthe cutters to be removed.'

Vters down far enough'to .allow themto removed from the mandrel and th'iefseaztr 'When thecutters have;beenugsharpened, 70 they may be replacedv and nested ether, as shown in Figs. 1 and8, and thef 39, be slipped over the cutters tolgio A -positi'on 'preparatory to in!" sertingthem into the pipeor'jcasin `d when after the cutters are llower casing, 4the ring 39 is intercepted of the casing and may then be4 dra the reduced portion t2y of the body, tool may be lowered intooperating 'position below' the casing. Y y .When the cutters are nested tege" e1 i practically cov-er the entire :cross-su tr'nal, area of the'casing 19, andul'lienftliey pfass underangular reamer and rin divergent jr'el'at oiv'nlin paths tothe expanded posit'i mum portion 4of the 'cross-'Sectio be reamed out under the casln'g fore, the under-reaming is effected in .such a way as to avoid the objections Vhereinbefore stated. i

As clearly seen in Figs. 1, 2 and 53, 9a and 16 Athe lower vend of the box bV is free from; any side slots or openings' intothef box which terminates in an unbrokenv rim id and has the conical chq" ber o'r cavity 3 forms the Vseat for the Shanks. By reason of this construction, there is practically no liability' l l of wear between the Shanks of the cutters and the end ofthe box, and consequently t-he body will ontlast a great number oftentters, and the expense and loss ofV time required with otherreameis to send the'body to the shopto have the cutters fitted to it is Furthermdre, by reason ofV the conical shape of the cavity, and the Shanks of the nested4 cutters'yi'eldingly held thereimrthe body is adapted to lift ofi" of'the cutter 'Shanks in case the cuttersfbecome Astuck inw the hole, and to allowthe cutter blades to collapse and withdraw from the walls of the'h'ole so that 'liability of any sticking of thetool in the holeiis minimized,

Owing to the co struction shown whereby the tips of the shi'iiibs are adapted to rest on the intermediate sloping shoulders 21 when the tool is collapsed,'and at the same time the riders can ride' along the casingthe ex pension and contraction of the cutters Yasj y @6l y they pass out of and into the casing is effected within smoothnessvof action that avoids vsticking andl to the efficiency and 'Wearing qualities of the tool; and further-J mor the-tip resting on the intermediate shou nerrelev'es the riders from excessive pressure against the casing, thus allowin the use of'a strong retracting spring witllr minimized friction on thecasing and gradual reduction from the mouth to the seat of the bore, avoids jer s and jars as the cutters are brought from expanded to collapsed positionfland vice versa.

LA' reciprocating under-'remuer providedvvith Inore'thantwo cutters the blades of 'v'hich are adapted and arranged to move radiallyl -relative to the axis-'of'the underrearner vand in divergentrelatively angular paths substantially as and for the purpose set forth, and a body provided in its lovrer end with a seat; said cutters projecting beloir' said body and havingfshanks that' nest in the seat .when thetool is expanded.

A .reci nrocating underfrealner more thantvvo cutters having Shanks in'the seatland having blades that project dovvn -rom the body. and are radially movable iin divergent relatively angular paths, and that practlcaflly nest-with each vother *when* reives smoothness o f action and' provided 1n its ower end with'a seat and wlth.

i "hij 4. The combination \vitha body having a longltudlnal bore, an end seat and a transverse slot; of a slotted mandrel in the bore; cutters pivoted to the mandrel and having Shanks in the seat; a key in the slots of the,I

body and mandrel to limit the movement of themandrel. and means to yieldingly hold the mandrel to seat the cutters in the seat.

A reciprocating under-.remuer .provided vvith more than tvvo cutters in pivotal relation vvith'each other. that form the lower pable of practically nesting together when the tool is collapsed.

end of the tool. the blades thereof being ea- In testimony whereof, I have hereunto set I my hand at Los Angeles, California, this 17th day of January 1911.

, ')L L. DUNN. In presence of* i 4 i .Jam-:s R. Toivxsnxn, L. BELLE Rice. 

